Purple Thistle (Cirsium horridulum)
Aster Family (Asteraceae)
Purple thistle is an annual to biennial herb, reaching 5.5 feet tall. The stems are usually branched. The long, deeply incised leaves are spiny and clasp the stem. The leaves form a basal rosette from which the stem arises. The reddish purple to lavender or yellow flowers are in large spiny heads (3 inches broad). The spiny floral bracts may be green, purple, or white. Flowers mostly from spring to fall. Butterflies, bees, wasps, beetles, and other insects visit the flowers. It is a larval host plant for several butterflies. Seeds are dispersed by wind. Found mostly in the eastern US, Bahamas, southern Mexico, and Central America. It occurs in marshes, salt marshes, shores, fields, prairies, pinelands, and disturbed areas like roadsides. Grows in full sun and usually in nutrient-poor, moist to dry soils. Considered a weed in some areas. Also known as yellow thistle, bull thistle, horrible thistle, and spiny thistle. Listed as endangered in CT, NH, and PA; and threatened in RI.
Copyright Brett Miley
